The hypothesis of this proposal is that the interaction of tuberculosis and HIV during active tuberculosis and at sites of M.tuberculosis infection, predisposes the host to progression of HIV disease through both virologic and immunologic events and that the interaction of macrophages with T cells plays a central,role in this process. The specific aims of the proposal are 1. Determination of the role of the interaction of macrophages with T-cells in supporting expansion of HIV burden and enhanced HIV cytopathicity in patients with tuberculosis. 2. Determination of HIV genotype (V3 loop heterogeneity) and phenotype (SI/NSI and co-receptor usage) both systematically and locally in HIV-infected patients with tuberculosis. 3. Determination of anti-HIV cellular (CD4 and CD8) and humoral (neutralizing antibody) immune reponses at the time of diagnosis of tuberculosis both systemically and locally in HIV infected patients with tuberculosis.